This invention relates to a separate lubricating system for outboard engines and more particularly to an improved lubricating system for two cycle engines.
In conjunction with two cycle engines, it has been proposed to provide a separate lubricating system wherein the lubricating oil is contained within a separate tank and delivered to the engine lubricating system and eventually the combustion chambers wherein it may be burned after it has served its lubricating function. Such an arrangement overcomes the necessity to mix the lubricating oil with the fuel and further insures more positive lubrication of all components of the engine. However, in many instances the lubricant tank cannot be positioned in such a way so that it can supply the lubricating system of the engine by gravity feed. For example, when the system is used in conjunction with an outboard motor, it is not possible to mount a tank of sufficient capacity directly on the motor so as to provide the desired lubrication, particulary during long running periods. When the engine is of the large displacement type or is operated for long periods of time, it is impossible to provide a tank of sufficient capacity carried directly by the engine.
It has been proposed to eliminate these problems by supplying a separate, external oil tank which supplies either a small tank mounted on the engine or the engine itself by means of a pump. Where the pump is positioned in the engine there is a long supply line from the external tank to the pump. Thus, when the engine is started there is the disadvantage that the pump will have lost its prime or, alternatively, may run for a period of time without actually delivering any lubricating oil until the supply pipe is filled. Of course, this can cause detrimental damage to the engine. Also, such systems are disadvantageous in that the supply of lubricant to the engine will be dependent upon the viscosity of the lubricating oil. Furthermore, when the pump is driven continuously by the engine such systems will deliver more oil than necessary during periods of time when the engine is run at high speeds so as to result in unnecessary lubricating oil consumption.
It is, therefore, a principal object of this invention to provide an improved lubricating system for a two cycle engine.
It is a further object of this invention to provide a lubricating system for two cycle engines wherein a flow of lubricating oil to the engine is insured at all times and unnecessary oil consumption is avoided.
It is a further object of this invention to provide a separate lubricating system for an outboard motor wherein a continuous flow of lubricating oil is insured even during start up operation.